摘要
Cu-core solder joints are promising interconnections for 3D IC. The joints are able to possess a long lifetime under thermal-electrical coupling reliability tests. Apart from that, the microstructure inside the tested joints is truly fascinating. Due to the core structure in the joint, there are two short paths for electrons and atoms to migrate during electromigration tests. Besides, complicated phase evolution was revealed at the interfaces in the joint. In this study, Cu-core solder joints underwent a 750-hour thermal-electrical test. Subsequently, elemental analyses were carried out to probe the phase distribution and to interpret the evolution at the interfaces in tested joints.